As a mobile communication network develops, a plurality of communication systems, such as Global System for Mobile Communication (GSM), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), and Worldwide Interoperability for Microwave Access (WiMAX) based on IEEE 802.16 standard, exist together in a single terminal. A single terminal supports the plurality of communication systems using multiple communication modules (ex. modems) employed in the single terminal. The single terminal that supports the plurality of communication systems is called a complex terminal.
Meanwhile, after the complex terminal, including a built-in Universal IC Card (UICC), completes a process for subscriber identification, the complex terminal may use a service to access to a corresponding communication system. Conventionally, techniques for controlling the UICC are divided into a method using multiplexing (MUX) and a method not using MUX.
The method not using MUX defines a master UICC reader controlling the UICC physically, referred to as a master modem. That is, when a slave UICC reader (as called a slave modem) accesses to the UICC, the master modem replaces the slave modem as a UICC reader (referred to as an “instruction”). The master modem, receiving the instruction, transmits and receives commands or responses for communicating with a UICC instead of the slave modem. The master modem forwards the response received from the UICC, to the slave mode.
In the method using MUX, a variety of UICC readers share signals for communicating with the UICC
As described above, the mater modem should communicate with the UICC instead of the slave modem in the method not using MUX. Generally, the complex terminal operates only one modem of a plurality of modems and keeps other modems in an idle mode for using a power effectively, except a handover and a roaming. However, when the slave modem has to communicate with the UICC, the master modem on idle mode awakes and has to communicate with the UICC instead of the slave modem. Therefore, the master modem consumes the power until the slave modem ends communications with the UICC.
In the method using MUX, whenever an active communication modem is changed, a connection to the UICC is changed and power consumption is saved. After a first communication modem is connected to the UICC, Cold Reset should be performed so that a second communication modem is newly connected to the UICC. For this, it is difficult for the complex terminal to keep the connection between the first communication modem and the UICC and control the connection between the second communication modem and the UICC.